1. Field
This document relates to an electronic device with a touch sensor and a driving method thereof.
2. Related Art
As various types of electronic devices, e.g., home appliances or portable information devices, are becoming more lightweight and slimmer, the user input means is being switched from a button switch to a touch sensor. Accordingly, electronic devices, such as recently launched displays, each have a touch sensor (or touch screen).
A capacitive sensor, a type of touch sensor, detects the presence or absence of a touch and the coordinates of the touch by sensing a change in mutual capacitance when a human finger or conductive material touches or approaches the capacitive sensor. To measure a change in mutual capacitance and assess touch information, the procedure of configuring sensor nodes on the touch screen, outputting a drive signal, sensing a change in the mutual capacitance of the touch screen, and binarizing data is carried out.
The capacitive sensor senses a change in mutual capacitance caused by a human finger or conductive material, classifies a sensed signal as a touch only when the peak level of the sensed signal is at or above a threshold, and submits a touch report.
In order to improve the sensing performance of the touch screen, a noise suppression filter for suppressing the effects of noise is required. A conventional noise filtering algorithm removes impulse noise in sensing data by aligning the sensing data and then deleting (or blanking out) the minimum and maximum values of the aligned data.
The conventional noise filtering algorithm causes a reduction in the number of samples of sensing data because the minimum and maximum values of aligned data are deleted. When the number of samples is reduced, the use of an alignment filter leads to a decrease in signal-to-noise ratio (SNR), which needs to be overcome.